title: Evaluation of Candida acidothermophilum in ethanol production from lignocellulosic biomass.
abstract: A Saccharomyces-cerevisiae-based simultaneous saccharification and fermentation (SSF) of lignocellulosic biomass is limited to an operating temperature of about 37 degrees C, and even a small increase in temperature can have a deleterious effect. This points to a need for a more thermotolerant yeast. To this end, S. cerevisiae D5A and a thermotolerant yeast, Candida acidothermophilum, were tested at 37 degrees C, 40 degrees C, and 42 degrees C using dilute-acid-pretreated poplar as substrate. At 40 degrees C, C. acidothermophilum produced 80% of the theoretical ethanol yield, which was higher than the yield from S. cerevisiae D5A at either 37 degrees C or 40 degrees C. At 42 degrees C, C. acidothermophilum showed a slight drop in performance. On the basis of preliminary estimates, SSF with C. acidothermophilum at 40 degrees C can reduce cellulase costs by about 16%. Proportionately greater savings can be realized at higher temperatures if such a high-temperature SSF is feasible. This demonstrates the advantage of using thermophilic or thermotolerant yeasts.
authors.affiliation: Biotechnology Center for Fuels and Chemicals, National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Kadam
authors.forename: S L
authors.initials: SL
authors.lastname: Schmidt
mesh_terms: D018533:Biomass; D002175:Candida / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008031:Lignin / Q000378:metabolism*; D013696:Temperature
chemical_list: C036909:lignocellulose; D000431:Ethanol; D002482:Cellulose; D008031:Lignin; D005947:Glucose